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Clinical Methods I > Retinoscopy > Flashcards

Retinoscopy Flashcards

1
Q

what is an objective measurement?

A

a measurement and evaluation you make as a doctor with limited patient involvement

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2
Q

examples of objective measurements in assessment of refractive error

A
  • keratometry
  • retinoscopy
  • autorefraction
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3
Q

examples of subjective measurements in assessment of refractive error

A

manifest (subjective) refraction

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4
Q

what is a subjective measurement?

A

when a subject participates in this data collection, doctor is in charge but patient guides evaluation

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5
Q

image point, when an object is at infinity, is where

A

light rays converge in the back of the eye

when light is coming IN to the system

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6
Q

another name for the far point is the:

A

anterior focal point

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7
Q

what is the far point?

A

the location of the farthest object on which the fully relaxed eye can focus

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8
Q

what type of rays from the retina are involved in far point?

A

diverging rays from the retina

when light is going OUT of the system

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9
Q

image point and far point for:

Emmetropia

A

image point: at the retina

far point: at infinity

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10
Q

image point and far point for:

Myopia

A

image point: in front of the retina

far point: closer than infinity

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11
Q

image point and far point for:

Hyperopia

A

image point: behind the retina

far point: “beyond” infinity

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12
Q

what are the two factors that contribute to Ametropia?

A
  • power of the optical system (cornea + lens)

- axial length of the eye (distance to retina/ screen)

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13
Q

how does the “power of the optical system” influence ametropia in the case of myopia?

A

the more “plus” in a system, the more “powerful” the eye, and light rays converge sooner (in myopia)

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14
Q

how does “Axial length of the eye” influence ametropia in the case of hyperopia?

A

the shorter the distance from the front of the eye to the retina, the less distance rays have to converge, and so they may not be fully converged at the retina (in hyperopia)

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15
Q

what is astigmatism?

A

when there are two image “points” that are really image lines

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16
Q

importance of meridians in astigmatism

A
  • two principle meridians that give rise to two image lines

- one meridian will focus in front of the other (Can be either horizontal or vertical line)

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17
Q

where can the line images in astigmatism be?

A

these line images can either be in front of the retina, behind the retina, or one of them on the retina

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18
Q

where are image “points” (lines) in:

simple myopic astigmatism

A

one at the retina

one in front of the retina

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19
Q

where are image “points” (lines) in:

simple hyperopic astigmatism

A

one at the retina

one behind retina

20
Q

where are image “points” (lines) in:

compound hyperopic astigmatism

A

both behind the retina

21
Q

where are image “points” (lines) in:

compound myopic astigmatism

A

both in front of the retina

22
Q

where are image “points” (lines) in:

mixed astigmatism

A

one in front and one behind

23
Q

goal of retinoscopy is to

A

objectively neutralize the patient’s refractive error

24
Q

retinoscopy is done by placing the ___ point where?

A

far point of the patient’s principle meridian(s) coincident with the doctor’s retinoscope

25
Q

moving the streak of the retinoscope across the patient’s eye produces a

A

a movement of the patient’s retinal reflex

26
Q

when does this “neutralization” of the movement occur?

A

when the lenses used by the doctor place the patient’s far point at their retinoscope (working distance)

27
Q

with-motion is observed when the far point of the eye is:

A

behind the viewing aperture

between the aperture and infinity

28
Q

against-motion is observed when the far point of the eye is:

A

between the eye and the viewing aperture

29
Q

neutral motion is observed when the:

A

retina and the aperture are in conjugate focus

30
Q

the features of the retinoscopic reflex are affected by:

A

the location of the eye’s far point in relation to the viewing aperture of the retinoscope

31
Q

as the far point moves closer/further from the aperture, what features may be affected?

A

width, brightness, and speed of the reflex

32
Q

as the far point moves closer to the aperture, what occurs to the reflex features?

A

the width, brightness, and speed of the reflex increase

33
Q

what meridian is being evaluated when the retinoscope is oriented vertically?

A

180 degree meridian is evaluated

34
Q

what meridian is being evaluated when the retinoscope streak is oriented horizontally?

A

90 degree meridian is evaluated

35
Q

what is it called when the reflex is misaligned with the stream beam?

A

break

36
Q

what is it called when the movement of the reflex is misaligned with the stream beam?

A

skew

37
Q

what occurs to the brightness when reflex is misaligned with the streak beam?

A

reflex is dimmer

38
Q

what occurs to the width of the reflex when it is misaligned with the steak beam?

A

the reflex is wider with less defined margins

39
Q

what is the working distance? how is it measured?

A

it is the distance from the eye that you hold your retinoscope, and it is based on the length of your arm

40
Q

what are the 2 working distances?

A
  1. 5D for 67cm or

2. 0D for 50cm

41
Q

if the far point of the patient’s eye is behind your scope, you will see ____ motion

A

with motion

42
Q

see with motion -> add what power?

A

plus power

43
Q

see against motion -> add what power?

A

minus power

44
Q

if the far point of the patient’s eye is in front of your scope, you will see _____ motion

A

against

45
Q

the gross findings for retinoscopy is when:

A

lenses are in place that allow “neutral” motion to be seen in all meridians
-far point(s) at plane of retinoscope

46
Q

steps of retinoscopy:

A
  1. scan all meridians of the eye
  2. determine the most plus (least negative) meridian and neutralize that meridian first
  3. once all meridians ar neutralized (gross findings), remove your working distance lens to determine the patient’s refractive correction (net findings)
47
Q

what kind of motion do you see in emmetropes and what does that mean?

A

see with motion, which means the far point is behind

Clinical Methods I (5 decks)

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